I did a search and found a post in the Ducati forum that promoted the 10% front 20% rear tire inflation pressure increase rule. In other words, the hot air pressure should be 10% higher in the front or 20% higher in the rear. That’s sounds like a good rule to me.
I did a search and found a post in the Ducati forum that promoted the 10% front 20% rear tire inflation pressure increase rule. In other words, the hot air pressure should be 10% higher in the front or 20% higher in the rear. That’s sounds like a good rule to me.
It's a formula or rule. Don't know that I'd call it a good one.
To get a 20% increase in tire pressure on a tire that's at 40 psi cold at 80 degrees F, you've got to heat it up to 188 degrees F. That's one damn hot tire. I'd say it was under-inflated or overloaded to get a 20% pressure increase, and probably isn't going to last long.
A 10% increase in tire pressure on a tire with 40 psi at a cold temperature of 80 degrees has to be heated up to 134 degrees. That's much more reasonable.
If you want to play with the ideal gas law calculator for this, here's one that's pretty straight forward and easy to use. Since volume doesn't change, just set it to 1 unit of your choice.
This is what my FOBO was showing on a 2 up ride in the Black Hills last week. The rear started at 42 that am. This was early, while it was still cool. I was concerned about it being in the yellow, but it was within the 20 per cent rule. I was showing 109 degrees. I changed the parameters on the FOBO.
It's a formula or rule. Don't know that I'd call it a good one.
To get a 20% increase in tire pressure on a tire that's at 40 psi cold at 80 degrees F, you've got to heat it up to 188 degrees F. That's one damn hot tire. I'd say it was under-inflated or overloaded to get a 20% pressure increase, and probably isn't going to last long.
A 10% increase in tire pressure on a tire with 40 psi at a cold temperature of 80 degrees has to be heated up to 134 degrees. That's much more reasonable.
If you want to play with the ideal gas law calculator for this, here's one that's pretty straight forward and easy to use. Since volume doesn't change, just set it to 1 unit of your choice.
Well typically, it's about heat. You want the tire to flex enough to give a specific temp rise. But most don't have accurate temp capabilities... Plus just going from a garage to hot street is heat without going anywhere.
Bottom line is tire pressure cold is soft. Typical driving will heat to say 50psi... 50psi is proper riding temp even though that would be hard starting out cold.
At the end of the day it is a trade off between contact patch and wear. IIf I wanted max miles I would fill to max pressure... And it would feel like crap. Too soft wears out tires too fast. We want the ideal pressure for our bikes to give the best performance, and to do that, you need to figure out a proper heat or corresponding pressure rise. It's the best we can do. Race teams can do it much better.
You have to start somewhere, and OEM recommendation is not at all ideal for everyone.
For what it's worth. I watched a DaveMoss Video about tire pressures and basically threw out everything I knew or cared about tire pressure.
Then I went out and road my bike hard adjusting pressures until it felt right.
I landed on a very different PSI than the bike or tire intended pressures.
36/36 is the F/R cold I run for riding hard. 39/39 F/R cold for Touring/2up.
You can't setup a Harley quite the same as Dave does for sports/track bikes mind you
Actually you can, the problem is just that HD's bikes generally dont come with the dials and adjustors that would be nice for it.
But since I have an SE Ohlins shock, I got all the dials for the rear end. My front end however doesn't have any adjustments but it does have Intiminators in the forks with progressive springs which are dead on for rebound setup.
I dont have any rebound wear and tear signs at all. My front tire looks great, and grips great. Those intiminators are pretty neat.
Dave Moss can do cruisers to motoAmerica racers.
A bike is a bike is a bike.
There's actually very little real difference between setup for the track and setup for the street. The major dynamic that changes for the street is usually payload.
His advice about tire pressure and rebound, dead on for my bike. His methods work, and they work well. That's why people pay for him to do that stuff.
Then I went out and road my bike hard adjusting pressures until it felt right.
There ya go!
For in the end, that is what matters. Not spreadsheets, temperature recorders, etc.
How it works for you, under a given condition, is what matters.
My eyes were opened similarly by another writer some years ago. It was cars, a Miata in fact. But the basic message was the same. Tinker and tune until you get it the way you want it.
07-24-2024 | 09:54 AM
you went out and changed it 